So is it just a new way of organizing tabs? I'm not sure what the issue is with browsers having many tabs open, besides it being difficult to navigate between them (and obviously resource consumption)

Difficult navigation is enough of a problem. Seeing just a single letter of the page title because you have a hundred tabs open makes finding tabs really hard and cumbersome.

> besides it being difficult to navigate between them

That's it. Hierarchical pages makes it really easy to contextually browse or what I call "immutable browsing" which is never just clicking, but always ctrl+clicking links to never change your current page.

Also, the one thing many people don't realize is how easy it should be to close dozens of pages. A simple drag across the close buttons in Doogie (or drag over which ones you want) helps close swaths of pages.